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A049697 a(n)=T(n,n+1), array T as in A049695. 1
1, 3, 6, 10, 16, 22, 30, 40, 50, 60, 74, 88, 104, 122, 136, 152, 176, 198, 222, 248, 268, 290, 322, 352, 380, 412, 442, 472, 512, 548, 586, 632, 668, 704, 744, 780, 828, 882, 924, 964, 1020, 1072, 1126 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..42.

FORMULA

a(n-1)=sum_{k=1...n}mu(k)floor(n/k)ceiling(n/k); a(n) is asymptotic to (6/Pi^2)*n^2 - Benoit Cloitre, Jun 27 2005

PROG

(PARI) a(n)=sum(k=1, n++, n\k*moebius(k)*ceil(n/k)) \\ Charles R Greathouse IV, Mar 02 2012

CROSSREFS

Cf. A018805.

Sequence in context: A327141 A283503 A294481 * A111712 A293407 A194144

Adjacent sequences:  A049694 A049695 A049696 * A049698 A049699 A049700

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified August 15 13:59 EDT 2022. Contains 356145 sequences. (Running on oeis4.)